Darwinbots Forum
General => Biology => Topic started by: Numsgil on October 17, 2005, 02:04:48 PM
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When comparing animal and plant cells, the most striking difference is wha animal cells don't have.
Cell Walls, cellulose, vacuoles, or chloroplasts.
Well, then I begin to wonder which is the decision and which is the consequence. That is, because plant cells have cell walls, they need cellulose. They don't have cell walls because they have cellulose.
That is, cell walls was the decision and cellulose the effect.
So I'm just wondering about the overall cause/effect relationship between the four things above.
edit: basically I'm thinking our bots are most similar to diatoms. Some diatoms have chloroplasts when it's beneficial to have them, and then lose them and hunt other cells when it's beneficial to do that.
So diatoms represent to me the ultimate form I want Darwinbots to follow. (Not for just the above reason alone, but for others as well (their highly geometric shapes for another)).
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That is, cell walls was the decision and cellulose the effect.
Not necessarily. What if some process evolved to make cellulose then the cell figured out a way to use it afterward?
Other than that I agree that diatoms are probably the most DB like cells in real life.
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one mayor thing this cause is that plants dont need to move. they get food where they are. So then they dont have to waste energy on moving. But animals have. And then animals evolve muscles so they can move. But plants dont. But plants have to stand up, so they evolve harder cell wall or what you called to to keep it up with out muscles. And when they have evolved this thing they are basacly stuck, they are hard so the cells cant move or change. And from there is not so much to do. A few plants achived movements by differentthigns I dont know in english
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one mayor thing this cause is that plants dont need to move. they get food where they are. So then they dont have to waste energy on moving. But animals have. And then animals evolve muscles so they can move. But plants dont. But plants have to stand up, so they evolve harder cell wall or what you called to to keep it up with out muscles. And when they have evolved this thing they are basacly stuck, they are hard so the cells cant move or change. And from there is not so much to do. A few plants achived movements by differentthigns I dont know in english
But plants are being eaten by animals. It would make alot of sense for plants to run when it sees a herbivore coming its way.
Not moving is the effect, not the decision. Hard outer cells walls and woody plants are the effect, not the decision. Why? Because it is clearly advantgeous to move instead of not move unless it effects more critical abilities (like photosynthesizing).
I'm sure it comes back to chloroplasts at some point. I think they're the root (haha, a pun!) cause, even if indirectly, for the hard cell walls, large vacuoles, and cellulose.
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One reason plants do not move is because it would cost to much energy.
Also for the absorption of minerals plants have to dig into the ground.
Well and the only reason for aplant to move is to defend itself, but to defend itself it does not need to move.
Also the question is whats harder for a plant? to regrow what was eaten or to build up and maintain eyes, muscles,brain etc
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You're still examining effects and not the causes.
All a plant theoretically needs is CO2, water, and light. Everything else, the nutrients, etc, are neat little tricks plants have learned along the way. Anyway, a plant could always just evolve a mouth, eat some dirt, digest what it likes in the dirt, and defecate the rest.
Worms do this. It's obviously possible.
Animals obviously evolved to move. Common logic tells you if the choice is only between moving and not moving, you'd learn to move in response to being eaten.
Plants don't move because they have strong, hard, rigid cell walls. WHy do plants have cell walls? It helps to control the turgor pressure (osmotic pressure) of their vacuoles.
Well, why do plants have vacuoles? Animals seem to get by just fine without them, so they obviously have some relationship with things that animals don't have. Probably chloroplasts.
You can photosynthesize just as easily moving as not, so obiously plants are not rooted/have cell walls because they need them for photosynthesis. There must be something about photosynthesis with chloroplasts that demand a large vacuole, which then in turn directs a number of consequences.
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Maybe the evolution of the vacuoles and chloroplasts simultaneously was simply chance.
Do primitive algaes have vacuoles?
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Yeast have vacuoles. They don't do photosynthesis.
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Maybe the evolution of the vacuoles and chloroplasts simultaneously was simply chance.
there ya go.
evolution has very little to do which entities making 'choices'.
evolution exists independent of anything making choices ...
gypsy moths didn't 'choose' to mimic the bark of the trees they live on ...
they exist and continue to exist because for whatever reason ...
some mutation resulted in them matching the bark ...
and THAT is what increased their chances of survival and propagation.
evolution works because:
what works lives and continues ...
what doesn't work dies and doesn't.
period.
it has little to do with decision making or control ...
that's just we humans thinking we are somehow the end
product and crowning achievment of evolution and life.
pah!
we are only one tiny part of life ...
no more, no less ...
the web of life and it's diversity is awesome ...
compared to we puny little beings.
we are tiny little specks in the universe ...
and certainly don't seem to know our place ...
we still think it is all about us. ;)
life, evolution, nature ... is indifferent ...
it isn't complicated, it's simple ...
what works continues ...
what doesn't ends.
who knows ...
earth may have a few billion years left ....
perhaps some intellegent life form may yet evolve.
[perhaps you can tell ...
I'm not all that impressed with humans ...
I think we've made rather a mess of things.] :D
jijimuge:
all things and events are mutually interpenetrating and interdependant.
~griz~
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Perhaps choice is too strong a word.
Basically everything an organism has is either an adaptation or a result of an adaptation.
We have chins, for example, because of the way our jaws have evolved, not because chins are a magnificent adaptation.
Chins are the effect, jaws the decision.
Did a little thinking. Could it be that the large vacuoles allow a plant cell to have more surface area than otherwise without a huge metabolic cost?
Vacuoles are basically just a large sac of water, so that would support such a conclusion.
The larger surface area is then surrounded by chloroplasts. The result is a much increased ability to photosynthesize.
That the woody parts of plants have vacuoles too, even though they don't photosynthesize could just be that cells have a hard time unevolving something once it's evolved. Basically the woody parts of plants must follow the path of their leafy forefathers.
That makes alot of sense, someone tell me if something in my reasoning is off...
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Did you look for vacuoles at wikipedia? There are many roles for them, not just turgor.
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Well yes, but there are other ways to accomplish what vacuoles do without the limiting effects on locomotion, etc.
Heterotrophic cells seem to rarely have vacuoles, which makes sense when your drag is directly related to your surface area, and you'll need to move around to find your food.
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griz, cant you finish the sentence to the end instant of pressing enter all the time?
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griz, cant you finish the sentence to the end instant of pressing enter all the time?
of course I 'can' ...
but I choose not to ...
that's just my style man ...
I write as if I'm speaking out loud ...
as if doing some poetry slam/jam ...
you know ...
with pauses ...
as if I'm actually alive ...
and breathing.
besides ...
I figure with you A.D.D. affected folks here ...
I should keep it short so you don't lose your train of thought. :D
~griz~
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hu?
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hu?
A.D.D. = attention deficit disorder ...
come'on admit it...
all us geeks got it.
but I don't consider it neccessarily a disorder ...
actually, it's essential for multitasking ...
as long as one doesn't get too carried away. ;)
~griz~
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Guess we had better break out the Ritalin then.
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Ritalin is what let's me work on Darwinbots for 4 hours without getting distracted. Great stuff. :lol:
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I dont have ADD, and I know it. But I have something else wich einstein/newton/beethoven had. HA
but I seemn to have prooblem getting air, cause you look for air before uve even finished a sentence, as you said before.
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A simple answere is energy management:
Photosynthesis does not deliver enough energy for the cell that does photosynthesis to move, its barely enough energy to reproduce self, and it does not have to move (only its childrens have to move away from the parent, generally done by wind).
The sun is not always shining, but storing energy is easier than searching sunnier places, that are plopably out of reach anyways!!!
Animals that eat many cells that do photosynthesis can get enough energy for movement, and they have to move to find enough food because it only grows were they are not eating! They are less dependant on dark or dry periods and more flexible in finding energy sources.
Animals that eat animals can get even more energy and have to move even more and are even more flexible (most can still eat plants, too)...
The suns energy at one place at first gets used by cells that do not move. Than it gets used by slowly moving cells that collect that stored energy from a few places. Than it gets used by faster moving cells that collect the stroed energy from a few slowly moving cells...
Animals do not develop solar collectors because eating plants is just easier and if an animal could do photosynthises its ability to move would be ambiguous like a whales foot.
There are also lithorve bacteria eating rocks and sand, they move really slowly.
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I hadn't looked at it from the food web/pyramid energy levels perspective before. That's rather interesting...
Course, while that applies to macroscopic animals, I think that sort of reasoning breaks down at the protist level.
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And then there is the case of certain marine animals who have symbiotic Alga called zoozanthellae.
Take this nudibranch for example
(http://img389.imageshack.us/img389/4416/solarslug4fj.jpg)
You can read more about it Here (http://www.seaslugforum.net/factsheet.cfm?base=solarpow)
Then there are the corals which derive most, if not all their energy from sugars which their zozanthellae provide. Admitedly they don't move about a whole lot.